Dell PowerConnect B-RX BigIron RX Series Configuration Guide v02.8.00 - Page 747

Configuring RIP parameters 24 Configuring redistribution You can configure the device to redistribute routes learned through OSPF or BGP4, connected into RIP, or static routes. When you redistribute a route from one of these other protocols into RIP, the device can use RIP to advertise the route to its RIP neighbors. To configure redistribution, perform the following tasks: • Configure redistribution filters. You can configure filters to permit or deny redistribution for a route based on its origin (OSPF, BGP4, and so on), the destination network address, and the route's metric. You also can configure a filter to set the metric based on these criteria. • Change the default redistribution metric (optional). The device assigns a RIP metric of one to each redistributed route by default. You can change the default metric to a value up to 16. Configuring redistribution filters RIP redistribution filters apply to all interfaces. You use route maps to define how you want to deny or permit redistribution. NOTE The default redistribution action is permit, even after you configure and apply redistribution filters to the virtual routing interface. If you want to tightly control redistribution, apply a filter to deny all routes as the last filter (the filter with the highest ID), then apply filters to allow specific routes. A route map is a named set of match conditions and parameter settings that the router can use to modify route attributes and to control redistribution of the routes into other protocols. A route map consists of a sequence of up to 50 instances. If you think of a route map as a table, an instance is a row in that table. The router evaluates a route according to a route map's instances in ascending numerical order. The route is first compared against instance 1, then against instance 2, and so on. As soon as a match is found, the router stops evaluating the route against the route map instances. Route maps can contain match statements and set statements. Each route map contains a "permit" or "deny" action for routes that match the match statements. • If the route map contains a permit action, a route that matches a match statement is permitted; otherwise, the route is denied. • If the route map contains a deny action, a route that matches a match statement is denied. • If a route does not match any match statements in the route map, the route is denied. This is the default action. To change the default action, configure the last match statement in the last instance of the route map to "permit any any". • If there is no match statement, the software considers the route to be a match. • For route maps that contain address filters, AS-path filters, or community filters, if the action specified by a filter conflicts with the action specified by the route map, the route map's action takes precedence over the individual filter's action. If the route map contains set statements, routes that are permitted by the route map's match statements are modified according to the set statements. In RIP, the match statements are based on prefix lists and access control lists. Set statements are based on tag values and metric values. To configure redistribution filters, enter a command such as the following. BigIron RX(config-rip-router)#redistribute bgp route-map longroute BigIron RX Series Configuration Guide 671 53-1002253-01